Diaphragm pump guaranteed with operational reliability

ABSTRACT

Provided is a diaphragm pump guaranteed with operational reliability that enables a fluid to be continuously sucked and discharged by causing a volume change of an working chamber through a diaphragm pulsating according to the flow of compressed air controlled by movement of a spool constituting an air control valve, and smoothly can pump a fluid by reliably controlling the flow of compressed air using an up-and-down motion of a spool performed by pressure of the compressed air, and thus completely resolving an inoperative situation caused by a delay in motion of the spool. The diaphragm pump includes: a pump body ( 10 ), a shaft ( 20 ), a first diaphragm ( 30 ), a second diaphragm ( 40 ), and an air control valve ( 50 ).

REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Korean Patent Application No. 10-2013-0097022 filed on Aug. 16, 2013, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates, in general, to a diaphragm pump which enables a fluid to be continuously sucked and discharged by causing a volume change of a working chamber through a diaphragm pulsating according to the flow of compressed air controlled by movement of a spool constituting an air control valve, and, more particularly, to a diaphragm pump guaranteed with operational reliability which can smoothly pump a fluid by steadily controlling the flow of compressed air using an up-and-down motion of a spool performed by pressure of the compressed air, and thus completely resolving an inoperative situation caused by a delay in motion of the spool.

BACKGROUND OF THE INVENTION

Generally, a diaphragm pump is a small capacity metering pump for sucking and discharging a fluid by making a pair of diaphragms pulsate by using compressed air as driving power, can pump various fluids according to a material change of the diaphragms, is convenient to use due to a small volume and light weight, and can be stably used in a self-suction operation method.

The diaphragm pump has a structure in which a fluid is sucked in a fluid chamber and is then discharged to the outside by making a pair of diaphragms, connected to each other by a shaft, pulsate together in the same direction according to the flow of compressed air incoming or outgoing from an air chamber so that the capacity of the fluid chamber can be repeatedly changed, the pair of diaphragms dividing a working chamber provided at both sides of a pump body into the air chamber and the fluid chamber in a state of being installed at both ends of the shaft installed to be movable to the left and right of the pump body.

At this time, the flow of the compressed air is controlled by an air control valve, and the air control valve is configured such that a spool is installed in an inner side of a valve body. Movement of the spool is naturally caused in process of the working of air pressure resulting from the compressed air flowing through the atmosphere.

That is, when the spool is located below an inner side of the valve body, the compressed air flows in the air chamber of the left working chamber along an inflow passage groove of the spool to cause an increase of a capacity of the air chamber, the left diaphragm is pressed in a left direction to pulsate to the left along the shaft with the right diaphragm, and at the same time, the compressed air, which has been already entered into the air chamber of the right working chamber, is discharged through an exhaust passage of the pump body to the outside along an outflow passage groove of the spool.

Accordingly, the fluid, which has been already sucked in the fluid chamber of the left working chamber, is discharged through a discharge pipe to the outside, and a new fluid is sucked in the vacant fluid chamber of the right working chamber through a suction pipe.

Furthermore, when the shaft is completely moved to the left, an upper space of the valve body communicates with the outside through the exhaust passage to cause the working of air pressure, and at the same time, the compressed air flowing through the inflow passage groove of the spool is discharged through the inside of the spool to the exhaustion passage of the pump body, and the spool is moved up again, and thus is located at an upper part of the valve body due to a pressure difference.

Then, as the compressed air flows in the air chamber of the right working chamber along the inflow passage groove, the capacity of the air chamber is increased, so the right diaphragm is pressed in a right direction to pulsate to the right along the shaft along with the left diaphragm, and at the same time, the compressed air, which has already entered the air chamber of the working chamber, exits through the exhaust passage of the pump body to the outside along the outflow passage groove of the spool.

Accordingly, the fluid, which has been already sucked in the fluid chamber of the right working chamber, is discharged through the discharge pipe to the outside, and a new fluid is sucked in the vacant fluid chamber of the left working chamber through the suction pipe.

As the aforesaid situations are repeated, the fluid is alternately sucked in and discharged from the fluid chamber of the left working chamber and the fluid chamber of the right working chamber, thereby enabling continuous pumping.

However, the conventional diaphragm pump has a structure in which lifting and lowering motions of the spool are generated in a low pressure situation by air pressure, and there is no packing for steadily controlling the flow of compressed air on an outer circumferential surface of the spool.

Accordingly, as the compressed air leaks through gaps due to tolerance limitations between the spool and the valve body, the working of air pressure is not properly maintained, the up-and-down motion of the spool is not smoothly performed, so the spool is delayed in motion at an ambiguous position inside the valve body, thereby causing an inoperative situation.

To solve this problem, there has been suggested a diaphragm pump which is configured such that an O-ring is installed on an outer circumferential surface of a spool so as to prevent compressed air from leaking, and a pilot valve operated by the physical pressure of a diaphragm and for enabling high pressure by the compressed air to work in an upper side space and a lower space of the spool is further installed so that the up-and-down motion of the spool can be smoothly performed.

However, the conventional diaphragm pump is problematic in that the whole structure of the pump is complex, increasing the number of constitutive elements as well as increasing assembly time, and increasing unit price of the product because the pilot valve is further installed.

In order to completely solve these problems possessed by the conventional diaphragm pump, there is an urgent need to develop a diaphragm pump having an air control valve which enables the up-and-down motion of a spool to be smoothly performed even without a separate additional element.

The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and the present invention is intended to propose a diaphragm pump guaranteed with operational reliability which is configured such that an up-and-down motion of a spool for controlling the flow of compressed air for enabling pulsating of a diaphragm is smoothly performed by only an air control valve even with a separate additional element such as a pilot valve so that an inoperative situation due to the delay in motion of the spool can be solved.

The object of the present invention is not limited to the object mentioned above, and other objects not mentioned above will be clearly understood based on the following disclosures.

In order to achieve the above object, according to one aspect of the present invention, there is provided a diaphragm pump guaranteed with operational reliability, including: a pump body having a discharge pipe and a suction pipe installed at an upper side and a lower side thereof, respectively, provided with an exhaust port opening onto the outside, and divided into a first working chamber and a second working chamber connected to the suction pipe and the discharge pipe of the left and right, respectively; a shaft installed to be movable to the left and right of the pump body and having one end and another end configured to protrude to the interior of the first working chamber and the second working chamber, respectively; a first diaphragm and a second diaphragm installed at one end and another end of the shaft, respectively, and for dividing the first working chamber into a first fluid chamber and a first air chamber, and the second working chamber into a second air chamber and a second fluid chamber, respectively; and an air control valve including a valve body installed at the pump body and provided with an air inlet, and a spool installed to be vertically movable at an inner side of the valve body and for controlling the flow of compressed air incoming and outgoing of the first air chamber and the second air chamber, wherein the air control valve is configured such that when the shaft is completely moved to the right or left while the first air chamber or the second air chamber is filled with compressed air, the compressed air of the first air chamber or the second air chamber flows in a lower space or an upper space of the valve body through a first air outflow passage or a second air outflow passage to enable a lifting or lowering motion of the spool to be performed, and thus the compressed air, which has already entered in the upper space or the lower space of the valve body, along with the compressed air of the first air chamber or the second air chamber are discharged through the exhaust port to the outside, and at the same time, new compressed air entering from the air inlet flows in the second air chamber or the first air chamber, so that a fluid is sucked in the first fluid chamber or the second fluid chamber by making the first diaphragm and the second diaphragm pulsative to the right or left along the shaft, thereby ensuring continuous pumping of the fluid according to discharge of the fluid sucked in the second fluid chamber or the first fluid chamber.

The spool may have a plurality of protruding flanges formed to protrude on an outer circumferential surface thereof while having an up and down distance so as to be divided into: a first pressure space whose upper space is an inner side of the valve body; a second pressure space whose lower space is the inner side of the valve body; a first exhaust space for communicating the first air chamber and the exhaust port; a second exhaust space for communicating the second air chamber and the exhaust port; and an inflow space for communicating the first air chamber and the second air chamber with the air inlet, wherein an O-ring being in close contact with an inner circumferential surface of the valve body and for enabling the divided spaces to be sealed is installed at an outer side of the protruding flanges.

The first air outflow passage and the second air outflow passage may be provided between a shaft hole into which the shaft is inserted and the shaft and may be opened by a first opening and closing means or a second opening and closing means when the shaft is fully moved to the right or left so that the first air chamber and the second air chamber can open onto the lower space and the upper space arranged at the inner side of the valve body, namely, the second pressure space and the first pressure space of the valve body, respectively.

The first opening and closing means and the second opening and closing means may include: a pair of O-rings installed on left and right inner circumferential surfaces of the shaft hole and having a certain distance; and grooves formed on left and right inner circumferential surfaces of the shaft, respectively, wherein when the shaft is fully moved to the right or left, the grooves are collinearly placed with the O-rings located at an outer side adjacent to the second air chamber or the first air chamber, and thus, a gap generated therebetween enables the second air chamber and the first air chamber to open onto the first pressure space and the second pressure of the valve body, respectively.

The exhaust port may be divided into: a first exhaust port for discharging the compressed air flowing in the first air chamber through the first exhaust space to the outside; a second exhaust port for discharging the compressed air flowing in the second air chamber through the second exhaust space to the outside; and a third exhaust port for discharging the compressed flowing in the first pressure space and the second pressure space of the valve body to the outside.

An outlet side of the first exhaust port and an outlet side of the second exhaust port may be configured to open onto each other, and an outlet side of the third exhaust port may be configured not to open onto the outlet sides of the first exhaust port and the second exhaust port.

Each of the first exhaust port and the second exhaust port may have an internal diameter which is gradationally or gradually increased toward an outlet.

According to the embodiment of the present invention, as the motion of the spool is controlled by pressure resulting from compressed air rather than air pressure, an inoperative situation due to a delay in motion of the spool is settled so that the flow of the compressed air for making the diaphragms pulsative can be certainly controlled and thus pumping of the fluid can be continuously and smoothly performed, thereby ensuring operational reliability.

Furthermore, as the motion of the spool is controlled by only the compressed air without the need of a separate pilot valve, parts can be reduced, a simple structure and easy assembly can be realized, and a unit price of the product can be reduced.

Also, as compressed air for controlling the motion of the spool is discharged through a separate exhaust port different from the exhaust port from which compressed air for making the diaphragms pulsate is discharged to the outside, the motion of the spool is not influenced by an icing phenomenon generated at the time of discharging the compressed air for making the diaphragms pulsate so that the motion of the spool can be normally maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an operational view illustrating a diaphragm pump showing a state in which a fluid is sucked in a first fluid chamber and is discharged from a second fluid chamber;

FIG. 2 is an operational view illustrating a diaphragm pump showing a state in which the fluid is sucked in a second fluid chamber and is discharged from a first fluid chamber;

FIG. 3 is an enlargement view of part “A” in FIG. 1; and

FIG. 4 is an enlargement view of part “B” in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A diaphragm pump guaranteed with operational reliability according to the present invention is a small capacity metering pump driven by the flow of compressed air and is mainly installed in a ship in order to prepare for flood conditions of the ship due to seawater

In particular, unlike a conventional diaphragm pump, the diaphragm pump guaranteed with operational reliability according to the present invention is characterized in that it can ensure operational reliability by resolving an inoperative situation caused by a delay in motion of a spool and can also reduce a unit price of the product by using only an air control valve without a pilot valve.

This characteristic is realized by a structure in which the spool constituting the air control valve controls the flow of compressed air coming in and out of an air chamber while performing a lifting motion by the high pressure of the compressed air that fills the air chamber.

Accordingly, as the spool reliably controls the flow of the compressed air coming in and out of the air chamber while forcibly performing a lifting motion by high pressure of the compressed air, the fluid can be continuously pumped by making a pair of diaphragms, connected to each other by a shaft, pulsate together in the same direction.

Herein below, the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an operational view illustrating a diaphragm pump showing a state in which a fluid is sucked in a first fluid chamber and is discharged from a second fluid chamber, FIG. 2 is an operational view illustrating a diaphragm pump showing a state in which the fluid is sucked in a second fluid chamber and is discharged from a first fluid chamber, FIG. 3 is an enlargement view of part “A” in FIG. 1, and FIG. 4 is an enlargement view of part “B” in FIG. 1.

As illustrated in FIGS. 1 and 2, a diaphragm pump guaranteed with operational reliability according to a preferred embodiment of the present invention includes: a pump body 10; a shaft 20; a first diagram 30; a second diagram 40; and air control valve 50.

First, the pump body 10 includes a center block 11 being central thereto, and side blocks 12, 13 installed at both sides of the center block 11, respectively, which constitutes the whole form of the diaphragm pump.

Here, the side blocks 12, 13 are divided into a first working chamber 14 arranged at an inner side of the left side block 12, and a second working chamber 15 arranged at an inner side of the right side block 13, respectively. A discharge pipe 16 and a suction pipe 17 are installed at an upper side and a lower side of the side blocks 12, 13, respectively.

That is, both ends of the discharge pipe 16 communicate with an upper side of the first working chamber 14 and an upper side of the second working chamber 15, respectively, and both ends of the suction pipe 17 communicate with a lower side of the first working chamber 14 and a lower side of the second working chamber 15, respectively. Further, a discharge hole 16 a is formed in the center of the discharge pipe 16, and a suction hole 17 a is formed in the center of the suction pipe 17.

However, a check valve 16 b opened only in a direction in which a fluid is discharged from the first working chamber 14 and the second working chamber 15 to the discharge pipe 16 is installed at an inlet side of the discharge pipe 16, and a check valve 17 b opened only in a direction in which a fluid is sucked from the suction pipe 17 to the first working chamber 14 and the second working chamber 15 is installed at an inlet side of the suction pipe 17.

An exhaust port 18 opening onto the outside is provided at one side of the pump body 10.

Next, the shaft 20 is horizontally movably inserted into a shaft hole 19 formed in the pipe body 10 and connects the first diaphragm 30 and the second diaphragm 40 to be opposite to each other, thereby enabling the first diaphragm 30 and the second diaphragm 40 to integrally communicate with each other.

That is, the shaft 20 is installed so that one end and another end thereof protrude to the first working chamber 14 and the second working chamber 15, and connects the first diaphragm 30 and the second diaphragm 40 installed at one end and another end thereof to be integrally pulsating facing each other in the interior of the first working chamber 14 and the second working chamber 15.

Next, the first diaphragm 30 and the second diaphragm 40 are installed at one end and another end of the shaft 20, respectively, to be opposite to each other. The first diaphragm 30 and the second diaphragm 40 enable an inner space of the first working chamber 14 to be divided into a first fluid chamber 14 a and a first air chamber 14 b, and an inner space of the second working chamber 15 to be divided into a second air chamber 15 b and a second fluid chamber 15 a, respectively, so as to pulsate by the pressure of compressed air incoming and outgoing between the first air chamber 14 b and the second air chamber 15 b, thereby enabling the fluid to be sucked in and discharged through the first fluid chamber 14 a and the second fluid chamber 15 a.

That is, the first diaphragm 30 and the second diaphragm 40 are installed between the left side block 12 and the center block 11, and between the right side block 13 and the center block 11, respectively, and are caused to pulsate by compressed air which alternatively flows in the first air chamber 4 b and the second air chamber 15 b and enable the fluid which alternatively flows in the first fluid chamber 14 a and the second fluid chamber 15 b to be discharged to the outside, thereby enabling continuous pumping of the fluid to be performed.

The suction pipe 17 and the discharge pipe 16 suck in the fluid from the outside and discharge it to the outside, respectively, and both ends thereof communicate with the first fluid chamber 14 a of the first working chamber 14 and the second fluid chamber 15 a of the second working chamber 15, respectively.

Next, the air control valve 50 is installed at the pump body 10, and controls compressed air incoming and outgoing of the first air chamber 14 b of the first working chamber 14 and the second air chamber 15 b of the second working chamber 15.

That is, the air control valve 50 enables the compressed air to flow in the first air chamber 14 b and the second air chamber 15 b, or the compressed air flowing in the first air chamber 14 b and the second air chamber 15 b to be discharged, thereby enabling the first diaphragm 30 and the second diaphragm 40 to pulsate horizontally along the shaft 20 according to a pressure change of the interior thereof.

Here, the air control valve 50 includes: a valve body 51 installed at the pump body 10 and having an air inlet 51 a formed at one side thereof and injecting compressed air from the outside; and a spool 52 vertically movably installed at an inner side of the valve body 51 to control flow of the compressed air injected from the air inlet 51 a.

That is, when the first air chamber 14 b or the second air chamber 15 b is filled with the compressed air, and the shaft 20 is completely moved to the right or left, the compressed air of the first air chamber 14 b or the second air chamber 15 b flows out through a first air outflow passage 53 or a second air outflow passage 54 and then flows in a lower space or an upper space of the valve body 51.

At this time, the spool 52 performs an up-and-down motion at the inner side of the valve body 51 by pressure of the compressed air flowing in the lower space or the upper space of the valve body 51. Thus, the spool 52 enables the second air chamber 15 b or the first air chamber 14 b to communicate with the air inlet 51 a and to flow new compressed air injected from the air inlet 51 a in the second air chamber 15 b or the first air chamber 14 b.

At the same time, the first air chamber 14 b or the second air chamber 15 b is open to exhaust port 18 so that the compressed air of the first air chamber 14 b or the second air chamber 15 b can be discharged through the exhaust port to the outside.

The first diaphragm 30 and the second diaphragm 40 are simultaneously pulsated to the right or left along the shaft 20 by pressure resulting from the compressed air

Accordingly, as illustrated in FIG. 1 or FIG. 2, the fluid is sucked in the first fluid chamber 14 a or the second fluid chamber 15 a, and the fluid, which has been already sucked in the second fluid chamber 15 a or the first fluid chamber 14 a, is discharged, thereby enabling continuative pumping of the fluid to be performed.

At this time, as illustrated in FIG. 3, the spool 52 enables an internal space of the valve body 51 to be divided into a first pressure space 51 b, a second pressure space 51 c, a first exhaust space 51 d, a second exhaust space 51 e, and an inflow space 51 f.

That is, the spool 52 is configured such that a plurality of protruding flanges 52 a protrude on an outer circumferential surface of the spool 52 while having an up and down distance, thereby enabling the valve body 51 to be divided into the spaces. An O-ring 52 b for sealing the spaces while being in close contact with an inner circumferential surface of the valve body 51 is installed at an outer side of the protruding flanges 52 a.

Thus, the compressed air drawn into and discharged through the spaces is reliably controlled by the O-ring 52 b, thereby ensuring a lifting motion of the spool 52 generated due to pressure of the compressed air.

Here, the first pressure space 51 b and the second pressure space 15 c are the upper space and the lower space of the valve body 51 where the compressed air filled in the second air chamber 15 b and the first air chamber 14 b enters through the second air outflow passage and the first air outflow passage 53

The first exhaust space 51 d is a space intended to discharge the compressed air of the first air chamber 14 b to the outside by communicating the first air chamber 14 b and the exhaust port 18 with each other. The second exhaust space 51 e is a space intended to discharge the compressed air of the second air chamber 15 b to the outside by communicating the second air chamber 15 b and the exhaust port 18 with each other. The inflow space 51 f is a space intended to enable the compressed air to selectively flow in the first air chamber 14 b and the second air chamber 15 b by selectively communicating the first air chamber 14 b and the second air chamber 15 b with an air inlet 51.

Here, the first air inflow passage 53 and the second air inflow passage 54 are provided, as illustrated in FIG. 4, between the shaft hole 19 into which the shaft 20 is inserted, and the shaft 20.

That is, the first air outflow passage 53 and the second air outflow passage 54 are maintained in a closed state, and when the shaft 20 is completely moved to the left or right, the first air outflow passage 53 and the second air outflow passage 54 are completely opened by a first opening and closing means 55 and a second opening and closing means 56 so that the second air chamber 15 b and the first air chamber 14 b can open into a first pressure space 51 b and a second pressure space 51 c of the valve body 51, respectively.

The first opening and closing means 55 and the second opening and closing means 56 include a pair of O-rings 55 a, 56 b installed with a certain distance on inner circumferential surfaces on left and right sides of the shaft hole 19; and grooves 55 b, 56 b formed on the inner circumferential surfaces on the left and right sides of the shaft 20, respectively.

That is, the first opening and closing means 55 and the second opening and closing means 56 enable the second air chamber 15 and the first air chamber 14 b to open onto the first pressure space 51 b and the second pressure space 51 c by a gap between the O-rings 56 a, 55 a, and the grooves 56 b, 55 b generated while the O-rings and the grooves located at an outer side adjacent to the second air chamber 15 b and the first air chamber 14 b are placed in one line when the shaft 20 is fully moved to the left or right.

At this time, the exhaust port 18 is divided into a first exhaust port 18 a, a second exhaust port 18 b, and a third exhaust port 18 c. The first exhaust port 18 a is a passage to discharge the compressed air flowing in the first air chamber 14 b through the first exhaust space 51 d to the outside.

The second exhaust port 18 b is a passage for discharging the compressed air flowing in the second air chamber 15 b through the second exhaust space 51 e to the outside. The third exhaust port 18 c is a passage for discharging the compressed air flowing in the first pressure space 51 b and the second pressure space 51 c to the outside.

Outlet sides of the first exhaust port 18 a and the second exhaust port 18 b are configured to open to each other, but an outlet side of the third exhaust port 18 c is configured to open to the outlets sides of the first exhaust port 18 a and the second exhaust port 18 b.

This is intended to ensure operation of the spool 52 by enabling discharge of the compressed air discharged through the third exhaust port 18 c and being in charge of the operation of smoothly lifting the spool.

That is, during the process in which the compressed air of each of the first air chamber 14 b and the second air chamber 15 is discharged through the first exhaust port 18 a and the second exhaust port 18 b, even though an icing phenomenon is generated due to a temperature difference with the outside, it is intended to smoothly discharge the compressed air without being influenced by the phenomenon.

Furthermore, each of the first exhaust port 18 a and the second exhaust port 18 b is configured to have a diameter an internal diameter which is gradationally or gradually increased toward an outlet. This configuration is intended to prevent an icing phenomenon while minimizing a temperature reduction by inducing pressure down gradationally or gradually during the process in which the compressed air is discharged to the first exhaust port 18 a and the second exhaust port 18 b.

As described above, as the diaphragm pump guaranteed with operational reliability according the present invention is configured such that the spool controls the flow of compressed air while performing the lifting motion by pressure of the compressed air and the O-ring installed in the spool certainly controls the compressed air, whereupon an inoperative situation caused in the conventional diaphragm pump can be settled, a structure can be simple, operational performance can be guaranteed and a unit price of the product can be reduced.

Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A diaphragm pump guaranteed with operational reliability, comprising: a pump body (10) having a discharge pipe (16) and a suction pipe (17) installed at an upper side and a lower side thereof, respectively, provided with an exhaust port (18) opening to the outside, and divided into a first working chamber (14) and a second working chamber (15) connected to the suction pipe (17) and the discharge pipe (16) of the left and right, respectively; a shaft (20) installed to be movable to the left or right of the pump body and having one end and the other end configured to protrude to the interior of the first working chamber (14) and the second working chamber (15), respectively; a first diaphragm (30) and a second diaphragm (40) installed at one end and the other end of the shaft (20) respectively, and for dividing the first working chamber (14) into a first fluid chamber (14 a) and a first air chamber (14 b), and the second working chamber into a second air chamber (15 b) and a second fluid chamber (15 a), respectively; and an air control valve (50) including a valve body installed at the pump body (10) and provided with an air inlet (51 a), and a spool (52) installed to be vertically movable at an inner side of the valve body (51) and for controlling the flow of compressed air entering and exiting from the first air chamber (14 b) and the second air chamber (15 b), wherein the air control valve (50) is configured such that when the shaft is completely moved to the right or left while the first air chamber (14 b) or the second air chamber (15 b) is filled with compressed air, the compressed air of the first air chamber (14 b) or the second air chamber (15 b) flows in a lower space or an upper space of the valve body (51) through a first air outflow passage (53) or a second air outflow passage (54) to enable a lifting or lowering motion of the spool (52) to be performed, whereupon the compressed air, which has already entered in the upper space or the lower space of the valve body (51), along with the compressed air of the first air chamber or the second air chamber are discharged through the exhaust port (18) to the outside, and at the same time, new compressed air entering from the air inlet (51 a) flows in the second air chamber (15 b) or the first air chamber (14 b), so that a fluid is sucked in the first fluid chamber (14 a) or the second fluid chamber (15 a) by making the first diaphragm (30) and the second diaphragm (40) pulsate to the right or left along the shaft, thereby ensuring continuous pumping of the fluid according to discharge of the fluid sucked in the second fluid chamber (15 a) or the first fluid chamber (14 b).
 2. The diaphragm pump of claim 1, wherein the spool (52) has a plurality of protruding flanges (52 a) formed to protrude on an outer circumferential surface thereof while having an up and down distance so as to be divided into: a first pressure space (51 b) whose upper space is an inner side of the valve body (51); a second pressure space 51 c whose lower space is the inner side of the valve body (51); a first exhaust space 51 d for communicating the first air chamber (14 b) and the exhaust port (18); a second exhaust space (51 e) for communicating the second air chamber (15 b) and the exhaust port (18); and an inflow space (51 f) for communicating the first air chamber (14 b) and the second air chamber (15 b) with the air inlet (51 a), wherein an O-ring being in close contact with an inner circumferential surface of the valve body (51) and for enabling the divided spaces to be sealed is installed at an outer side of the protruding flanges (52 a).
 3. The diaphragm pump of claim 2, wherein the first air outflow passage (53) and the second air outflow passage (54) are provided between a shaft hole (19) into which the shaft (20) is inserted and the shaft 20 and may be opened by a first opening and closing means or a second opening and closing means when the shaft (20) is fully moved to the right or left so that the first air chamber (14 b) and the second air chamber (15 b) can open onto the second pressure space (51 c) and the first pressure space (51 b) of the valve body (51), respectively.
 4. The diaphragm pump of claim 3, wherein a first opening and closing means (55) and a second opening and closing means (56) include: a pair of O-rings (55 a, 56 a) installed on left and right inner circumferential surfaces of the shaft hole (19) while having a certain distance; and grooves (55 b, 56 b) formed on left and right inner circumferential surfaces of the shaft, respectively, wherein when the shaft 20 is fully moved to the right or left, the grooves are collinearly placed with the O-rings located at an outer side adjacent to the second air chamber (15 b) or the first air chamber (14 b), and thus, a gap generated therebetween enables the second air chamber (15 b) and the first air chamber (14 b) to open onto the first pressure space (51 b) and the second pressure (51 c) of the valve body (51), respectively.
 5. The diaphragm pump of claim 2, wherein the exhaust port 18 is divided into: a first exhaust port (18 a) for discharging the compressed air flowing in the first air chamber (14 b) through the first exhaust space (51 d) to the outside; a second exhaust port (18 b) for discharging the compressed air flowing in the second air chamber (15 b) through the second exhaust space (51 e) to the outside; and a third exhaust port (18 c) for discharging the compressed flowing in the first pressure space (51 b) and the second pressure space (51 c) of the valve body (51) to the outside.
 6. The diaphragm pump of claim 5, wherein an outlet side of the first exhaust port (18 a) and an outlet side of the second exhaust port (18 b) are configured to open onto each other, and an outlet side of the third exhaust port (18 c) is configured not to open onto the outlet sides of the first exhaust port (18 a) and the second exhaust port (18 b).
 7. The diaphragm pump of claim 5, wherein each of the first exhaust port (18 a) and the second exhaust port (18 b) has an internal diameter which is gradationally or gradually increased toward an outlet.
 8. The diaphragm pump of claim 6, wherein each of the first exhaust port (18 a) and the second exhaust port (18 b) has an internal diameter which is gradationally or gradually increased toward an outlet. 